1,1,5-trihydro-perfluoropentane as an inhalation anesthetic

ABSTRACT

THE NOVEL COMPOUND 1,1,5-TRIHYDRO-PERFLUOROPENTANE HAVING THE FORMULA CHF2(CF2)3CH2F IS DISCLOSED. THIS COMPOUND IS USEFUL AS AN INHALATION ANESTHETIC AND AS A SOLVENT AND DISPERSANT FOR FLUORINATED MATERIALS.

United States Patent M 3,729,567 1,1,5-TR1HY DRO-PERFLUOROPENTANE AS ANINHALATION ANESTHETIC Ross C. Terrell, Plainfield, N.J., assignor toAirco, Inc., New York, N.Y. No Drawing. Filed July 15, 1971, Ser. No.163,102

Int. Cl. A61k 27/00 US. Cl. 424-350 2 Claims The novel compound 1,1,5trihydro-perfluoropentane having the formula CHF (CF CH F is disclosed.This compound is useful as an inhalation anesthetic and as a solvent anddispersant for fluorinated materials.

This invention relates to the compound 1,1,5-trihydroperfluoropentane,and its use in producing anesthesia in anesthetic-susceptible,air-breathing mammals.

The compound 1,l,5-trihydro-perfluoropentane has the following formula:

CHF (CF CH F This compound is normally a clear, colorless liquid and hasthe following physical properties: boiling point 82.5 C.; vapor pressure90 mm. at 25 C.; specific gravity 1.4; and molecular weight 234.

The product 1,l,S-trihydro-perfiuoropentane is soda lime stable and ananesthetic for anestheic-susceptible mammals. This compound is alsoeasily miscible with other organic liquids including fats and oils andhas useful solvent properties, for example, as a solvent for fiuorinatedolefins and other fiuorinated materials such as fiuoro waxes. Thecompound of this invention may be used to prepare pastes and dispersionsof such materials useful for coatings and the like, and may be used as adegreasing agent.

The following examples will illustrate the preparation,

Potassium fluoride (90 g.) was added to N-methyl pyrrolidone (600 ml.)and the mixture dried by distilling out 100 ml. of the solvent. Thetosylate of 1-H, l-H, S-H- perfluoropentanol (CHF CF CF CF CH OTs) (288g.) was then added slowly while keeping the reaction temperature atl90-200 C. The product (127 g.) was distilled out as formed and waspurified by fractional distillation. The product was non-flammable andanalyzed as follows:

C H F -Calculated (percent): F, 73.0. Found (percent): F, 72.8.

In order to determine the potency of 1,1,5-trihydro-perfluoropentane asan inhalation anesthetic in combination with oxygen, tests were carriedout on mice. The product used was at least 99.5% pure as determined byvapor phase chromatography.

In the tests, 1,l,S-trihydro-perfiuoropentane is administered to testmice by a standard procedure in which a measured quantity of the agentis placed in a laboratory jar and allowed to completely evaporate so asto give a calculated vapor concentration. The test mice are then quicklyplaced in the jar and observed. Anesthesia is determined by observingthe righting reflex of the mice.

3,729,567 Patented Apr. 24, 1973 In such tests thel,1,S-trihydro-perfluoropentane induced a very light anesthesia in themice in 58 seconds at 4 vapor concentration. Moderate excitement wasobserved in the induction. Recovery required 40 seconds. Recovery timeis measured beginning when the mice are transferred from the test jar toroom air and ending when the mice are observed to be able to walk. At 5%vapor concentration essentially the same effects were observed but therewas also some depression in the respiration of the mice. Inductionrequired 45 seconds at this concentration and recovery required 1 minute20 seconds. At 6% vapor concentration the respiration rate fell to 40per minute. Induction was fairly smooth and required 55 seconds;recovery was uneventful and took 2 minutes and 18 seconds.

The compound 1,1,S-trihydro-perfluoropentane is a mild control over thepatient is desired or the amount of anesthetic administered is notregulated exactly. The anesthetic agent of the invention may beadministered by any of the well known techniques used for theadministration of general inhalation agents, such as the open drop,semiclosed, and closed systems. The agents may also be administered asan injectable anesthetic as taught by John C. Krantz, Jr., in U.S.Patent 3,216,897, issued Nov. 9, 1965 and assigned to the assignee ofthe instant application.

The compound of this invention lends itself to effective use as aninhalant anesthetic in respirable mixtures containing life-supportingconcentrations of oxygen as well as mixtures containing oxygen and otherinhalation anesthetics such as nitrous oxide. The effective amount ofthe compound of this invention to be employed depends on the level ofanesthesia to which the mammal is to be brought, the rate at whichanesthesia is to be induced, and the length of time over whichanesthesia is to be maintained. Minor volume percentages of the compoundin oxygen from several percent, for instance at least about 4%, up toabout 10% can be employed. The amount of anesthesia to be used can beregulated, starting with a small amount of the ether and graduallyincreasing the amount until the desired plane of anesthesia is reached.By then monitoring the physical reactions of the mammal, as is the usualprocedure, the duration and plane of anesthesia can be readilycontrolled.

While there has been described what are at present considered to be thepreferred embodiments of the invention, it will be understood thatvarious modifications may be made therein which are within the truespirit and scope of the invention.

I claim:

1. An inhalant anesthetic composition comprising 1,1,5-trihydro-perfluoropentane in admixture with oxygen in suitableproportions for anesthesia.

2. A method of anesthetizing an inhalation anestheticsusceptible mammalwhich comprises administering to said mammal by inhalation an effective,anesthetic amount of l,1,S-trihydro-perfluoropentane along withsufficient oxygen to support life.

References Cited Chemical Abstracts 56: 8198b to 8199a (1962).

JEROME D. GOLDBERG, Primary Examiner

